Ancient theorem relating side lengths in a right triangle: a2+b2=c2.
Glossary Term: Theorems
A list of geometrical theorems, rules, laws and tricks.
RHS congruence theorem states that, if the hypotenuse and side of one right-angled triangle are equal to the hypotenuse and the corresponding side of another right-angled triangle, the two triangles are congruent.
The angle formed between a chord and a tangent line to a circle is equal to the inscribed angle on the other side of the chord.
A circle tangent and secant intersect at a point P. If T is the tangency point and A and B are the secant’s intersection points with the circle, we have |PA|*|PB|=|PT|2
If two lines from the same point are both tangent to a circle, then the line from the point to the centre of the circle bisects the angle formed by the two tangents, and the point is equidistant from the two points of tangency.
The angle formed by connecting a diameter and another point on the circle is a right.
In any triangle, if a line intersects two sides of the triangle and is parallel to the third, then and only then the intersecting line divides the sides proportionally.